Why are my scans delivered at 72 DPI?

Our scanning machines output to 72 DPI, and we send you the scans that are produced by the scanning machine alone (we don't do corrections in Photoshop/Lightroom or artificially up-rez).

But "dots per inch" is only half of the equation when it comes to image size... The important measure of resolution for output is the pixel dimensions of an image. The more pixels something has, the more detail/definition in the image, which means a higher resolution.

Pixel dimensions are equal to the image size in inches multiplied by the number of pixels per inch, or PPI. PPI is similar to DPI, but not quite the same--one indicates the light-emitting digital units of measurement (pixels) while the others indicates physical ink-based units of measurement (dots). When you see the term DPI in Photoshop or Lightroom, it's actually referring to PPI (because DPI is actually determined by the printing machine). But the idea of DPI/PPI being only half the equation of image size remains the same.

For example, a photo that is 6 inches wide at 300 PPI (6 inches x 300 pixels = 1800 pixels) has the same number of pixels as a photo that is 25 inches wide at 72 PPI (25 inches x 72 pixels = 1800 pixels).

Learn more with Richard’s infographic on print resolution and the pixel dimensions needed for different print sizes; download it below: